Rust in Frame

Hi,

Picked up a used Trek the other day. The bike was practically new, but had set outside for an indefinate amount of time. It has some rust in the frame I'm assuming because when I take the aluminum seat post out, there is surface rust on that. What is the best way do treat this problem. A complete teardown and rebuild isn't out of the question.

a few thoughts...

2) most framesets have been aluminum since the mid to late 90's, and seat posts are either alloy or aluminum also.

3) likely you are looking at surface rust on non-aluminum parts

4) remove the seatpost, turn the bike upside down, and drain any water that is possibly inside the BB area.

5) you can give the bike a good cleaning and it should be fine. You should likely replace the chain if it looks as if it will cause any problems. And service the whole drive train, including the BB & headset.

Rust

Sorry for the confusion. You are correct sir.. aluminum doesn't rust. When I said there was rust on the aluminum seatpost, I meant it's an indicator there was rust inside the frame.
Most framesets are aluminum these days. There are those among us who like the absorbtion of a quality steel frame. The bike is a 98 steel flavor.. Trek's tripple butted chromium molybdenum. My question centers more around how to clean/treat rust that might be lurking within the frame instead of suface rust on components. My concern is rusting from the inside out..

all you can do is

as I said, remove seatpost and drain any water, then try to get some water inhibitor inside there like a light oil. It's unlikely that it will rust out, but certainly possible. But if no water drains out, you are likely dealing with surface rust only.

All that said, if you wash your bike and ride in the rain, you'll need to adopt the upside down drain trick as standard, as water will get in there. You can drill a small hole in the bottom of the BB to drain it, and fashion a drain jiggle valve to make sure it stays open by inserting a small piece of an old spoke or similar, large end inside the BB.

If you are up to it, I would say strip the frame then inspect the insides with the aid of a flash light. Remove as much dirt/corrosion by running a rag with the help of a stick. If you have access to a 12 gauge shotgun bore cleaner with a copper brush, run it thru the seat tube down to the bottom bracket then finish off with a swab from same rifle/shotgun cleaning kit.

There's a product called J P Weigel frame saver you can apply inside. There is only so much you can do as there is no way you can clean the insides of seat and chain stays. Down tube and top tube are sometimes inaccessible too.